It takes its name from the Aragonese Castle that stood in this area since 1300. In 1877 the castle was demolished and the space thus freed gave life to the square as we see it today in front of the contemporary La Marmora barracks.
In 1800 the square was the favorite spot for elegant walks and on holidays the music band played there. It became therefore the soul and the heart of the city. When Sassari then expanded, the ideal city center moved from Piazza Castello to the new great Piazza d’Italia.
In the 1950s, the demolition of some low buildings and the construction of two skyscrapers further modified the square. More recently, the numerous palm trees that shaded the square have been eliminated, because they were hit by the red weevil, a dangerous parasite that attacks especially this type of trees.
Under the square runs an archaeological path between the walkways and some underground rooms that had belonged to the Castle. The entrance is from a low glass block structure. The visit is really worth it.